Roller-type applicators for paints are well-known, and some are so designed that a hollow-roller serves as a reservoir for the paint that soaks through a porous roller during use. But no roller is known for applying adhesive (1) in which its hollow cylindrical body has normally closed longitudinally extending adhesive-dispensing slits that are opened by work-surface-pressed protuberances, and/or (2) in which the roller has radially flanged caps to guide the roller along the edge surface of a two-by-four lumber piece. It is the principal object of this invention to provide such an adhesive applicator.